Superadiabatic theory for Cooper pair pumping under decoherence

Juha Salmilehto and Mikko Möttönen
Phys. Rev. B 84, 174507 – Published 9 November 2011

Abstract

We introduce a method where successive coordinate transformations are applied to decrease the error in the adiabatic master equation resulting from truncation in the local adiabatic parameter. Our method reduces the nonphysical behavior stemming from the lack of complete positivity. The strong environment-induced relaxation at high Cooper pair pumping frequencies leads to adiabatic ground-state pumping only in the lowest-order approximation. We illustrate the robustness of the frequency where the adiabaticity breaks down using the high-order theory and show the emergence of an optimal environmental coupling strength, for which ideal pumping is preserved for the highest frequency. Finally, we study the effect of quantum interference on the pumped current and give an estimate for the relaxation rate of an experimentally measured system.

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  • Received 14 June 2011

DOI:https://doi.org/10.1103/PhysRevB.84.174507

©2011 American Physical Society

Authors & Affiliations

Juha Salmilehto1 and Mikko Möttönen1,2

  • 1Department of Applied Physics/COMP, Aalto University, P.O. Box 14100, FI-00076 AALTO, Finland
  • 2Low Temperature Laboratory, Aalto University, P.O. Box 13500, FI-00076 AALTO, Finland

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Issue

Vol. 84, Iss. 17 — 1 November 2011

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